Inclined manhole cover riser assembly

ABSTRACT

A riser assembly and method for engaging the same to raise a manhole cover to be flush with an inclined paved surface after the application of an additional layer of paving material thereto. The riser assembly includes a first and second riser frame with a plurality of specially manufactured spacer blocks fixedly secured between them. The spacer blocks have progressively different height dimensions and sloped upper surfaces so as to create an angle between the first and second riser frames. The angle is complementary to the slope of the paved surface. The riser assembly includes an expansion device for adjusting the diameter of the second riser frame so that it frictionally engages the existing manhole frame. The fixed securement of the spacer blocks prevents relative movement between the first and second riser frames even when the diameter of the second riser frame is changed.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to manhole cover supports. More particularly, this invention relates to a separate riser assembly that is placed within an existing manhole frame to raise the height of the manhole cover to compensate for added roadway pavement. Specifically, this invention is directed to a riser assembly for use with a manhole frame positioned on an incline. The riser assembly comprises a first riser frame and second riser frame having spacer blocks fixedly engaged between them in a manner that retains the first riser frame at an angle relative to the second riser frame. The inclined first riser frame supports the full circumference of the manhole cover at an angle complementary to the sloped road surface.

2. Background Information

Most underground facilities such as sanitary and storm sewers, utility conduits, and the like have manhole openings to provide access thereto. These manholes usually are located in the street or roadway and consist of an inverted, generally bell-shaped metal frame, mounted onto of a brick or concrete base structure. This metal frame has an internal, horizontal ledge for supporting the manhole cover so that the top of the cover is substantially level with the top of the frame and the surrounding roadway pavement.

Problems arise in the resurfacing of the roadways when a layer of pavement is placed on top of the existing pavement. This results in the manhole cover being positioned a distance below the top surface of the new pavement, causing a depression in the roadway. It is quite difficult and expensive to raise the existing manhole frame sufficiently to compensate for the added pavement. Thus, various devices and methods have been constructed and used which enable an existing manhole cover to be raised to the level of the new pavement surface without requiring the raising of the existing manhole frame.

One such device is disclosed in U.S. Pat. No. 7,165,911 (Fier). The patent discloses a riser assembly which supports a manhole cover and is engaged with a manhole frame. The riser assembly raises the height of the manhole cover to the new pavement level. The riser assembly includes a circular frame formed of a metal bar and has a locking ring attached thereto which extends vertically downwardly from the frame. A plurality of outwardly projecting tabs are formed in the locking ring and are adapted to engage the manhole frame to prevent upward movement of the riser. An expansion device expands the frame and locking ring outwardly, whereby the locking ring abuttingly engages a vertical surface of the manhole frame to assist in locking the riser assembly to the manhole frame.

The device disclosed in U.S. Pat. No. 7,165,911 works exceptionally well when the pavement surface surrounding the manhole is substantially flat. However, when the pavement surface is inclined, as would be the case if the manhole were located on a hill or in a valley, for example, then the riser assembly disclosed in U.S. Pat. No. 7,165,911 is not entirely adequate for the job. The reason for this is that there would be a tendency for one side of the manhole cover to be recessed into the inclined road surface or the manhole cover would tend to extend slightly above the angled pavement. Either of this situations leads to early degradation of the new pavement surface and simultaneously tends to be hazardous for vehicles traveling over the road.

Various devices have been proposed in the prior art to address the issue of how to raise a manhole cover to the level of a new pavement surface when that surface is inclined. For example, U.S. Pat. No. 6,799,920 to Sondrup discloses a device comprising a pair of angled rings that are stacked one above the other and together present a lower surface that is engageable with the manhole frame and an upper surface that supports the manhole cover. The rings are rotated relative to each other to vary the angle of the upper supporting surface of the device relative to the lower surface of the device. The rings may include markings that will permit the road crew to select the angle they want to create in the device so that it is able to support a manhole cover substantially flush with an inclined surface. In order to use the Sondrup device the road crew will take a variety of distance measurements relating to the manhole and the asphalt surrounding the same and will then calculate two rotational settings for the device. The upper and bottom rings are then rotated relative to each other to match the calculated rotational settings. If additional height is required, the device may further include a third ring that is interposed between the upper and bottom rings and is rotatable relative thereto. One of the issues with this device is that it requires the road crew installing it to make a series of calculations and adjustments to the device while they are busy installing the same. This need for doing calculations in the field tends to slow the installation process down. Additionally, Sondrup's frame has to be adjusted and installed prior to pouring the asphalt. The asphalt bonds to side of the frame. Then, each time an additional layer of asphalt is added to the road surface, the asphalt surrounding the frame has to be removed in order to adjust the rings to raise and tilt the manhole cover to be substantially level with the new road surface.

U.S. Pat. No. 5,944,442 (Roush et al) discloses an extender comprising two or more rings that are vertically stackable to adjust the overall height of the device so that it is able to support a manhole cover flush with a road surface. A first one of the rings has a plurality of vertical channels defined in the exterior surface of the side wall. A second one of the rings has a plurality of vertical channels on the interior surface of the side walls. The channels on the two rings are in complementary locations. Specially configured height-adjustable brackets are received in the channels of both rings to secure the rings to each other and to the base of the manhole frame. Additional rings may be similarly stacked with the first two rings. As asphalt is added to the roadway, the original rings may be disengaged from the base and be replaced with higher height rings. The side wall of each ring may be of a constant height around the ring's circumference or it may be manufactured so that it is higher at one end than at the other. At least one ring with a sloped side wall is used when the manhole is on a sloped road surface and there is a need to incline the manhole cover. Obviously, the slope of the side wall has to be calculated to fit each specific manhole so that after installation the manhole cover is flush with the inclined road surface.

Bowman (U.S. Pat. No. 5,051,022) discloses a device having a cast-iron top ring and a bottom ring that engage each other. The top ring receives the manhole cover therein and may be configured to tilt the cover. The bottom ring is configured to clamp under the seat of the existing manhole frame and when this occurs, the top ring of the device is seated on the uppermost rim of the existing manhole frame. The device is therefore limited to riser heights that are greater than the thickness of the manhole cover plus the thickness of the top ring. This arrangement is impractical in many instances because the average manhole cover thickness in the United States is 1¾″ to 3½″ thick and most asphalt overlays are around 1½″ thick. Consequently, Bowman's device is only useful in very specific instances. Additionally, when the turnbuckles on the device are expanded or contracted, Bowman's riser will not provide a flat surface upon which the manhole cover can rest. In each of the expanded or contracted positions, the riser will present an uneven surface upon which the cover will have to rest, leading to rocking of the cover as vehicles travel over the same. Additionally, the design of Bowman's device requires that the existing manhole frame include a lip where the cover rests so that the bottom ring can clamp to the same. However, many manhole frames do not include these lips and then the Bowman device cannot be used with these existing manhole frames.

Bowman (U.S. Pat. No. 5,143,478) discloses a riser assembly that is engageable with an existing manhole frame. The riser assembly includes a bottom ring that is seated on the horizontal support surface of the manhole frame upon which the cover previously rested. The riser assembly further includes an top ring that is linked to the bottom ring by two sets of spanners. The top ring has a greater diameter than the bottom ring and the spanners extend from the interior surface of the top ring to the upper surface of the bottom ring. Two of the spanners are welded to the interior surface of the top ring and to the upper surface of the bottom ring. These two spanners are stiff, flat steel bars that are positioned on either side of a turnbuckle device on the bottom ring. The remaining spanners are only welded to the interior surface of the top ring and are slidable over the upper surface of the bottom ring. The bottom ring will be positioned on the existing manhole frame and the turnbuckle will be adjusted to ensure that the bottom ring frictionally engages the frame. Since the two spanners adjacent the turnbuckle secure the two rings together, when the bottom ring's diameter is adjusted, the top ring's diameter is also adjusted. The remaining spanners slide over the upper surface of the bottom ring as the diameter of the top ring changes. The manhole cover is then seated on the spanners. The patent discloses that in some instance the spanners may have a top surface that is sloped. Consequently, when the manhole cover is seated on these sloped spanners, the manhole cover will be retained at an angle. This device is problematic for a number of reasons. Firstly, the top ring is positioned above the uppermost edge of the existing manhole frame. Consequently, both the uppermost edge of the manhole frame and the seat of the frame where the bottom ring sits will tend to wear and corrode. The load on the cover created when traffic travels over the same is supported by the bottom ring only. This bottom ring rests on the horizontal support or seat of the existing manhole frame. When traffic pushes down on the top ring, it creates a moment on the riser similar to a lever that creates a force to knock the cover and riser out of the manhole frame. Additionally, the cover is only supported by the spanners which are disposed at intervals between the upper and bottom rings. Consequently, as traffic moves over the cover, the cover will tend to rock on the spanners. This occurs because the cover is not supported around the full circumference thereof and when traffic runs over the edge of the cover in a location in-between the spanners it will create a force similar to a lever making the opposite side of the lid flip up. Still further, if the top surfaces of the spanners are sloped, when the size of the bottom ring is expanded or contracted the cover supported in the top ring will tend to either project above the rim of the top ring or sink inwardly relative hereto as the cover will be seated at a different location on the spanners in each of these instances. Additionally, because the top ring is disposed above the uppermost edge of the existing manhole frame, this riser assembly can only be used in specific applications because the riser heights have to be greater than the lid thickness plush the thickness of the base of the top ring.

There is therefore a need in the art for a device that is suitable for raising the height of a manhole cover on sloped terrain while avoiding some of the issues found with prior art devices.

BRIEF SUMMARY OF THE INVENTION

A riser assembly and method for engaging the same to raise a manhole cover to be flush with an inclined paved surface after the application of an additional layer of paving material thereto. The riser assembly includes a first and second riser frame with a plurality of specially manufactured spacer blocks fixedly secured between them. The spacer blocks have progressively different height dimensions and sloped upper surfaces so as to create an angle between the first and second riser frames. The angle is complementary to the slope of the paved surface. The riser assembly includes an expansion device for adjusting the diameter of the second riser frame so that it frictionally engages the existing manhole frame. The fixed securement of the spacer blocks prevents relative movement between the first and second riser frames even when the diameter of the second riser frame is changed.

The method of raising a manhole cover to the level of a top surface of an additional layer of paving material surrounding an existing manhole assembly comprises the steps of:

-   -   inserting at least one spacer block between an upper surface of         an annular second riser bar and a lower surface of an annular         first riser bar to create an angle between an upper surface of         the first riser bar and a lower surface of the second riser bar;     -   securing the at least one spacer block to each of the first and         second riser bars so that relative movement between them is         substantially prevented;     -   securing a flange to the first riser bar so that the flange         extends upwardly and outwardly away from the upper surface of         the first riser bar;     -   resting the lower surface of the second riser bar against a         horizontal support of the frame that is disposed adjacent the         vertical support; and     -   placing the manhole cover into a space bounded by the flange and         the upper surface of the first riser bar; and     -   resting a bottom perimeter of the manhole cover on the upper         surface of the first riser bar.         The method further includes the steps of:

activating an expansion device on the second riser bar; and

changing the diameter of the second riser bar using the expansion device so that an exterior surface of the second riser bar engages an angled flange of on the manhole frame.

The method further includes the steps of:

individually manufacturing a plurality of spacer blocks to have progressively different height dimensions and angled top and lower surfaces;

inserting the individually manufactured spacer blocks at specific locations between the first and second riser bars that will result in the angle being created between the first and second riser bars; where the angle is complementary to the slope of the new layer of paving material.

Finally, the method may further include the steps of:

welding a region of the lower surface of the first riser bar to an opposing region of the upper surface of the second riser bar.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A preferred embodiment of the invention, illustrated of the best mode in which Applicant contemplates applying the principles, is set forth in the following description and is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a top perspective view of a typical manhole installation in a paved surface;

FIG. 2 is an enlarged perspective view of the highlighted region of FIG. 1;

FIG. 3 is a cross-sectional view of the paved surface, the manhole and riser assembly taken through along line 3-3 of FIG. 1;

FIG. 4 is a cross-sectional view of the manhole and riser assembly taken along line 4-4 of FIG. 1;

FIG. 5 is a perspective view of a riser assembly in accordance with the present invention and showing a manhole cover from the manhole assembly that is engageable with the riser assembly;

FIG. 6 is an exploded perspective view of the riser assembly; and

FIG. 7 is a cross-sectional side view of the riser assembly.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, there is shown a paved surface or pavement 10 in which is defined an access hole 12 to a manhole assembly 14. A manhole cover 16 is engaged with manhole assembly 14 to close off access hole 12. Pavement 10 may be any type of surface including a road, a parking lot, a sidewalk etc. that includes a manhole assembly 14 and the paving material applied to pavement 10 may be asphalt, concrete or any other type of material that is applied in layers to form a rigid surface over which people and/or vehicles travel. In particular, the area of pavement 10 surrounding manhole assembly 14 is sloped in any one of a number of directions.

FIGS. 3 and 4 are cross-sections through pavement 10. FIG. 3 shows that manhole assembly 14 includes a manhole frame 28 disposed in a cavity 18 formed in a brick or masonry storm drain system 20 which is disposed beneath pavement 10. Pavement 10 comprises an original layer 22 of paving material and a new layer 24 of paving material. The region of pavement 10 within which manhole assembly 14 is situated is inclined at an angle “A” (FIG. 3) relative to the horizontal. FIG. 4 shows that the original layer 22 of paving material has an upper surface 22 a that is inclined. New layer 24 overlays original layer 22 and includes a top surface 24 a that is inclined at much the same angle “A” as the original layer 22.

Still referring to FIGS. 3 and 4, manhole frame 28 consists of a bell-shaped structure mounted in storm drain system 20 and includes a generally horizontal support surface 30 (FIG. 4) and a conical wall 32. Prior to the addition of new layer 24 of pavement 10, support surface 30 provided the seat for receiving and supporting manhole cover 16 thereon. Conical wall 32 terminates in an uppermost edge 33. Manhole frame 28 further includes a generally vertically extending interior surface 34 which extends downwardly from support surface 30. Interior surface 34 defines the actual manhole opening. Manhole frame 28 is configured to include an angle between the horizontal support surface 30 and conical wall 32 which matches the angled taper of the circumferential edge 16 a (FIG. 5) of cover 16. Preferably wall 32 is tapered to be complementary to edge 16 a of cover 16. Preferably, the angle between surfaces 30 and 34 will be 90° to facilitate the casting of manhole frame 28 as well as providing a complementary seat for cover 16. In accordance with a specific feature of the present invention, a manhole cover riser assembly 36 is utilized to raise up the level at which manhole cover 16 is supported when new layer 24 of pavement 10 is applied over the top surface 22 a of the original layer 22. Riser assembly 36 is configured so as to provide a seat for cover 16 so that it is substantially flush with the top surface 24 a of new layer 24. Furthermore, riser assembly 36 is provided to retain cover 16 at an inclined angle that is complementary to the angle of the inclined road surface that surrounds manhole assembly 14.

Referring to FIGS. 5-7, riser assembly 36 comprises a first riser frame 38, a second riser frame 40 and one or more spacer blocks 54 that are disposed between first and second riser frames 40 and are fixedly secured thereto. Spacer blocks 54 secure first and second riser frames 38, 40 against relative movement. More specifically, spacer blocks 54 substantially prevent first riser frame 38 from moving one or more of laterally, horizontally, radially, and vertically relative to second riser frame 40.

Preferably, each of the first and second riser frames 38, 40 is circular in shape when viewed from the top. It will be understood however that other shaped riser assemblies, such as square or rectangular assemblies, are considered to fall within the scope of the present invention. Furthermore, first riser frame 38 has a first perimeter and a first diameter and second riser frame has a second perimeter and a second diameter. First diameter and second diameter are substantially the same. Riser assembly 36 preferably is manufactured from any metal that is suitable for use in roadways, i.e., the metal has to be sufficient strong enough to take the loads placed on it and must be substantially rust and corrosion free. Riser assembly 36 also defines an opening 37 through which opening in the manhole frame 28 may be accessed.

First riser frame 38 comprises a substantially annular first riser bar 42 and a substantially annular flange 50. First riser bar 42 is generally square or rectangular in cross-section and has an upper surface 42 a, a lower surface 42 b, an interior side surface 42 c, an exterior side surface 42 d, a first end 42 e and a second end 42 f. The first perimeter of first riser frame 38 is defined by exterior side surface 42 d. The first perimeter is interrupted by a gap 46 a which is defined between first and second ends 42 e, 42 f of first riser frame 38. When riser is fully contracted, first and second ends 42 e, 42 f touch each other.

Flange 50 extends upwardly and outwardly from upper surface 42 a of first riser bar 42 and is secured thereto in any suitable manner, such as by an annular weld 52. Flange 50 is secured to first riser bar 42 in such a manner that an interior side surface 50 a of flange 50 is disposed at an angle “B” (FIG. 4) relative to upper surface 42 a of first riser bar 42. This angle “B” is complementary to the taper of the circumferential side wall 16 a of manhole cover 16. Interior surface 50 a of flange 50 defines an opening 66 that is complementary to manhole cover 16 that is to be received therein. When cover 16 is engaged with riser assembly 36, as will be hereinafter described, lower surface 16 b of cover 16 will be seated on upper surface 42 a of first riser bar 42 and the circumferential surface 16 a of cover 16 will abut interior surface 50 a of flange 50. It should be noted that flange 50 also includes a gap (not numbered) that is substantially aligned with gap 46 a and has an exterior side surface 50 b which is configured to be complementary to the access hole 12 provided in new layer 24 of pavement 10. Furthermore, flange 50 includes an uppermost edge 50 c that will be substantially aligned with top surface 24 a of the new layer 24 of pavement 10 when riser assembly 36 is engaged with manhole frame 28.

Second riser frame 40 comprises a second riser bar 44 and an expansion device 48. Second riser frame 40 preferably is formed from an annularly configured second riser bar 44 that is generally square or rectangular in cross-sectional shape. Second riser bar 44 includes an upper surface 44 a, a lower surface 44 b, an interior side surface 44 c, an exterior side surface 44 d, a first end 44 e and a second end 44 f. Second perimeter is defined by exterior side surface 44 d and is interrupted by a gap 46 b that is defined between first and second ends 44 e, 44 f of second riser bar 44. When riser assembly 36 is constructed, first riser bar 42 is disposed vertically above and aligned with second riser bar 44. Gap 46 a is also aligned with gap 46 b.

In accordance with yet another specific feature of the present invention, an expansion device 48 extends between first and second ends 44 e, 44 f of second bar 44. Expansion device 48 is provided to enable an installer to change the width of gap 46 b so as to fit riser assembly 36 into differently sized manhole frames 28. Preferably, expansion device 48 is a turnbuckle that is substantially identical to the turnbuckle assembly disclosed in U.S. Pat. No. 7,165,911, the disclosure of this patent being incorporated herein by reference. As such, the expansion device 48 includes a pair of threaded rods 68 each having a flange 70 at one end. Although not shown in these figures, it will be understood that each flange 70 defines an aperture therein that is alignable with one of a pair of vertically oriented holes 72 defined in second riser bar 44 of second riser frame 40. Holes 72 extend between upper and lower surfaces 44 a, 44 b of second riser bar 44 and each flange 70 fits into a horizontal slot 74 cut into each of the first and second ends 44 e, 44 f of bar 44 intermediate upper and lower surfaces 44 a, 44 b. A pin 76 is received through the aligned holes 72 and the aperture in flange 70. A turnbuckle 78 is engaged with the second ends of the two threaded rods 68. Each of the second ends is received within a bore (not shown) in turnbuckle 78. A hole 80 is defined in the turnbuckle 78 and is provided for insertion of a tool to rotate the turnbuckle 78 in either of a clockwise or counterclockwise direction and about an axis that runs through the rods 68. When turnbuckle 78 is rotated in one of a clockwise and counterclockwise direction, the first and second ends 44 e, 44 f of bar 44 will be drawn toward each other and the width of gap 46 b will decrease. When turnbuckle 78 is rotated in the other of a clockwise and counterclockwise direction, the first and second ends 44 e, 44 f will be moved away from each other and the width of gap 46 b will increase. It should be noted that when the width of gap 46 b decreases, the width of gap 46 a also decreases somewhat because the first and second riser frames are fixedly secured together by spacer blocks 54 and the two riser frames 38, 40 move in union with one another. Gaps 46 a and 46 b and not necessarily of the same size but preferably are centrally aligned with each other.

In accordance with a specific feature of the present invention, first riser frame 38 is disposed at an angle “A” (FIG. 7) relative to second riser frame 40. The angle “A” is complementary to the angle “A” at which the pavement 10 slopes as shown in FIG. 3. The angle “A” is created in riser assembly 36 by positioning one or more spacer blocks 54 between lower surface 42 b of first riser bar 42 and upper surface 44 a of second riser bar 44. Spacer blocks 54 are secured to first riser bar 42 by welds 56 and to second riser bar 44 by welds 58. Spacer blocks 54 are aligned with the first and second riser bars 42, 44, i.e., blocks 54 are aligned with the regions of first and second riser bars 42, 44 to which they are secured. When spacer blocks 54 inserted between first and second riser bars 42, 44, a gap 60 is defined between lower surface 42 b of first riser frame 38 and upper surface 44 a of second riser frame 40 in all regions of riser assembly 36 that are free of space blocks 54. As is evident from FIG. 4, gap 60 is wider toward one side of riser assembly 36 and is narrower toward the other side thereof, i.e., the gap 60 tapers in height from one side of riser assembly 36 to the other. It should be noted that once first riser frame 38 is fixedly secured to second riser frame 40 via the at least one spacer block 54, the angle “A” between the first and second riser frames 38, 40 is non-adjustable and will remain constant unless and until the welds 56, 58, 67 are broken and spacer blocks 54 are removed from between first and second riser frames 38, 40.

It will be understood that in accordance with the present invention, riser assembly 36 is custom made to be utilized in a specific manhole in pavement 10. It is desirable to custom make each riser assembly 36 so that it specifically suits the terrain of the pavement 10 into which it is to be installed. FIGS. 1, 3 & 4 show that pavement 10 slopes downwardly in a direction that is substantially parallel to the longitudinal axis “Y” of the road 11 (FIG. 1). The terrain may additionally slope at an angle relative to the longitudinal axis “Y”, but this is not illustrated on this attached figures. Consequently, in order to provide the correct angular orientation of riser assembly 36 so that it fits the specific terrain surrounding a particular manhole assembly 14, the dimensions and shapes of the various spacer blocks 54 are calculated and each spacer block is effectively custom made to be placed at a specific location around the circumference of first and second riser bars 42, 44.

The location of each spacer block 54 is calculated and the blocks 54 are placed in those specific locations between first and second riser frames 38, 40 in order to ensure that the correct angle and pitch necessary to suit the terrain is built into the riser assembly 38. If the spacer blocks are correctly shaped and secured between first and second riser frames 38, 40, the uppermost surface 16 c of cover 16 will be substantially flush with top surface 24 a of pavement 10. Additionally, if spacer blocks 54 are correctly shaped, positioned, and secured between first and second riser bars 42, 44, uppermost edge 50 c of flange 50 will be substantially flush with the top surface 24 a of the new layer 24 of pavement 10. If the blocks 54 are not of the correct shape or correct positioning, portions of the uppermost edge 50 c and of cover 16 will be disposed a distance above or below the top surface 24 a, thus creating an uneven sloped surface for vehicles to travel over or for people to walk on.

In accordance with a specific feature of the present invention, the variations in shape and size of spacer blocks 54 are the features that create the particular angle “A” that is required between first and second riser frames 38, 40. FIGS. 5 and 6 show a first spacer block 54 a provided proximate a first region 36 a of riser assembly 36. First region 36 a is opposite a second region 36 b that includes expansion device 48. First spacer block 54 a has a first height and both of its upper and lower surface 55, 57 are disposed substantially parallel to each other. A second spacer block 54 b is provided at a third region 36 c of riser assembly 36. Spacer block 54 b has a second minimum height that is smaller than the height of block 54 a. Additionally, the upper surface 55 of spacer block 54 b is disposed at an angle relative to the lower surface 57 thereof. Spacer block 54 c is located in a fourth region 36 d of riser assembly 36. Spacer block 54 c has a minimum height which is different to either of the heights of spacer blocks 54 a and 54 b. Additionally, the upper surface 55 of spacer block 54 c is disposed at a different angle relative to the lower surface 57 of block 54 c. In the second region 36 b of riser assembly 36, there are no spacer blocks secured between first and second riser frames 38, 40 and upper surface 44 a of second riser bar 44 is secured directly to lower surface 42 a of first riser bar 42, preferably by a weld 67. The angle “A” between first and second riser frames 38, 40 is configured in accordance with the slope of pavement 10 that manhole cover 16 has to be made level with. FIG. 3 shows that the slope “A” of pavement 10 is substantially equal to angle “A” and uppermost edge 50 c of riser assembly 36 is flush with top surface 24 a of pavement 10. It should be noted the angles of the upper surfaces 55 of each of the spacer blocks 54 a, 54 b, 54 c are selected so as to ensure that they support first riser bar 42 at angle “A”. Each block 54 may be manufactured to have a different height or slope on its upper surface 55. The heights of spacer blocks 54 a, 54 b, 54 c grow progressively shorter as you move from spacer block 54 a toward the region where first riser bar 42 is directly welded to second riser bar 44.

Riser assembly 36 in accordance with the present invention is used in the following manner. Firstly, a variety of measurements are taken by a road crew as relating to a particular manhole in which they wish to use an angled riser assembly 36 to raise manhole cover 16 so that it will be substantially flush with pavement 10. These measurements, including size of access opening 12, depth of new layer 24, slope “A” matching the road 11, and so on. These measurements are provided to a riser assembly manufacturer to construct an appropriate riser assembly. The manufacturer will figure out the specific dimensions of the spacer blocks 54 (namely blocks 54 a, 54 b, 54 c and so on) that are to be used in riser assembly 36. Additionally, the manufacturer will determine how many spacer blocks 40 have to be utilized and exactly where those spacer blocks 40 need to be placed between first and second riser bars 42, 44 in order to produce the angle “A” in riser assembly 36. Once this information is determined, riser assembly 36 is constructed. The relevant number of spacer blocks 54 a, 54 b, and 54 c are welded to first and second riser frames 38, 40 in the predetermined locations between lower surface 42 b of first riser bar 42 and top surface 448 a of second riser bar 44. If needed, and as shown, a region of first riser bar 42 is welded to a region of second riser bar 44. Expansion device 48 is also engaged with lower riser bar 42. The constructed riser assembly 38 is then shipped to the jobsite for installation in a specific manhole assembly 14.

At the jobsite the road workers or utility crew will remove the existing manhole cover 16 from the manhole opening 14. In the attached figures, this is accomplished by inserting a lifting tool (not shown) into the apertures 64 in cover 16. The upper surface 22 a of original layer 22 of pavement 10 will be suitably prepared, and the new layer 24 of pavement 10 will be applied over upper surface 22 a. Access hole 12 is then cleared to ensure that no debris or pavement material is disposed on the surfaces of manhole assembly 14. Riser assembly 36 is then inserted though access hole 12 and lowered until lower surface 44 b of second riser frame 40 comes into abutting contact with horizontal support surface 30 of manhole frame 28.

Riser assembly 36 is rotated, if necessary, within manhole opening 14 so that the uppermost edge 50 c of flange 50 is substantially level with the top surface 24 a of new layer 24 of pavement 10. When the uppermost edge 50 c is deemed level with top surface 24 a, expansion device 48 on second riser frame 40 is activated to increase the width of gap 46 b. Expansion device 48 increases the second diameter or, stated differently, increases the overall circumference of second riser frame 40 so that second riser frame 40 is tightly fictionally retained within the conical wall 32 of manhole frame 28. (It will be understood that other components and methodologies may be employed to engage riser assembly 36 with manhole frame 38, and these other methodologies are considered to fall within the scope of the present invention. When riser assembly 36 is correctly installed in manhole frame 28, a worker will not be able to pull riser assembly 36 upwardly or push it downwardly. When expansion device 48 is in the expanded condition, second riser bar 44 is wedged within the opening bounded by conical wall 32. At this stage, first riser frame 38 rises upwardly from second riser frame 40 and extends beyond uppermost edge 33 of conical wall 32. It should also be noted that riser assembly 36 is positioned within the space defined by conical wall 32 and no part of riser assembly 36 contacts uppermost edges 33. Flange 50 extends upwardly from first riser bar 42 and flange's uppermost edge 50 c is substantially flush with top surface 24 a of pavement 10. Upper surface 42 a of first riser bar 42 is disposed at an angle “A” relative to bottom surface 44 b of second riser bar 44.

Manhole cover 16 is then lowered into the opening 66 defined by flange 50. Bottom 16 b of cover 16 is disposed in abutting contact with upper surface 42 a of first riser bar 42 of first riser frame 38 and circumferential edge 16 a of cover 16 will abut interior surface 50 a of flange 50. Additionally, upper surface 16 c of cover 16 will be substantially flush with top surface 24 a of new layer 24 of pavement 10.

If it is later decided to add yet another layer of pavement material to pavement 10, riser assembly 36 may be quickly and readily disengaged from manhole frame 28. Firstly, cover 16 is removed from its abutting engagement with first riser frame 38 by inserting a tool through apertures 64 and lifting cover 16 out of opening 66 in riser assembly 36. Expansion device 48 is activated to reduce the width of gap 46 b in the expanded second riser frame 40. When expansion device is so activated, the second diameter or circumference of second riser frame 40 is decreased in size so that riser assembly 36 is no longer wedged into the space in manhole frame 28 defined by conical wall 32. It will be understood that the at least one spacer block 54 is stationary relative to both of the first and second riser frames 38, 40 when expansion device 48 is activated to change the second diameter of the second riser frame 40.

Riser assembly 36 is then lifted out of access opening 12. A newly custom-built riser assembly (not shown) that is configured to accommodate the additional layer of pavement may then be inserted through access opening 12 and then adjusted to frictionally engage manhole frame 28 in the manner described with reference to riser assembly 36.

The riser assembly in accordance with the present invention presents a cover-bearing surface (upper surface 42 a of first riser frame 38) that is always disposed at the same orientation whether the expansion device 48 is in a neutral position or in an expanded condition or a contracted condition. Consequently, a cover 16 engaged with riser assembly 36 when engaged with manhole assembly 14, and more specifically with manhole frame 28, will not tend to rock as vehicles travel thereover.

It will be understood that while the expansion device has been illustrated herein as being provided on second riser frame 40, an expansion device may alternatively or additionally be provided on first riser frame 38 without departing from the scope of the present invention.

It will be understood that second riser frame 40 may additionally include a locking ring (not shown) that extends downwardly from lower surface 44 b of second riser bar 44 and is configured to be receivable through the opening defined by the interior surface 34 of manhole frame 28. This locking ring may include components that will secure riser assembly 36 to manhole frame 28. The locking ring could be of a similar configuration to that disclosed in the U.S. Pat. No. 7,165,911 (Fier) previously incorporated herein by reference.

Any other suitable components for fixedly or releasably securing riser assembly 36 to manhole frame 28 are also considered to fall within the scope of the present invention. So, for example, second riser frame 40 may be welded to support surface 30 or may be secured to the annular lip which support surface 30 and interior surface 34 form part of, by fasteners, clamps etc

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention are an example and the invention is not limited to the exact details shown or described. 

1. A riser assembly for engaging a manhole cover with an existing manhole frame after the application of an additional layer of paving material onto an inclined paved surface surrounding the manhole frame; said riser assembly comprising: a first riser frame having an upper surface and a lower surface; said first riser frame being adapted to support the manhole cover so that the manhole cover is substantially flush with a top surface of the additional layer of paving material; a second riser frame having an upper surface and a lower surface; said second riser frame being adapted to engage a portion of the existing manhole frame, and wherein the first riser frame and second riser frame are vertically aligned with each other; at least one spacer block disposed between a first region of the lower surface of the first riser frame and a first region of the upper surface of the second riser frame; wherein the at least one spacer block is vertically aligned with the first and second riser frames; and wherein the upper surface of the first riser frame is disposed at an angle relative to the lower surface of the second riser frame; and wherein said spacer block is fixedly secured to each of the first and second riser frames and substantially prevents relative movement between the first and second riser frames.
 2. The riser assembly as defined in claim 1, wherein a second region of the lower surface of the first riser frame is fixedly secured to a second region of the upper surface of the second riser frame; and the second regions are disposed a distance away from the first regions.
 3. The riser assembly as defined in claim 1, wherein the at least one spacer block is fixedly secured to both of the first and second riser frames by a fixed securement and this fixed securement substantially prevents the first and second riser frames from moving one or more of laterally, radially, horizontally and vertically relative to each other.
 4. The riser assembly as defined in claim 1 further comprising: a gap defined between the lower surface of the first riser frame and the upper surface of the second riser frame in regions free of the at least one spacer block; and wherein the gap tapers in height in a direction moving away from the at least one spacer block.
 5. The riser assembly as defined in claim 1, further comprising a plurality of spacer blocks secured at intervals between the lower surface of the first riser frame and the upper surface of the second riser frame; wherein each of the plurality of spacer blocks is individually dimensioned and shaped to be secured at a different region between the first and second riser frames so as to create the angle between the upper surface of the first riser frame and the lower surface of the second riser frame.
 6. The riser assembly as defined in claim 1, wherein the first riser frame has a first perimeter and the second riser frame has a second perimeter; and wherein the first riser frame is disposed vertically above the second riser frame and the first and second perimeters are substantially vertically aligned with each other.
 7. The riser assembly as defined in claim 6, wherein the at least one spacer block is extends between the first and second riser frames and the regions of the first and second riser frames to which the spacer block is secured are vertically aligned with each other.
 8. The riser assembly as defined in claim 6, further comprising: an expansion device engaged with the second riser frame and being operable to change the size of the second perimeter thereof.
 9. The riser assembly as defined in claim 8, wherein the first riser frame comprises: an annular first riser bar having an upper surface, a lower surface, an interior surface, and an exterior surface; and wherein the upper surface of the first riser bar comprises the upper surface of the first riser frame and the lower surface of the first riser bar comprises the lower surface of the first riser frame; a flange extending upwardly and outwardly from the upper surface of the first riser bar and terminating in an uppermost edge; and a space bounded and defined by an interior surface of the flange and the upper surface of the first riser bar, and wherein the space is adapted to receive the manhole cover therein and when the manhole cover is so received, the upper surface of the first riser bar provides a substantially continuous support for a bottom perimeter surface of the manhole cover.
 10. The riser assembly as defined in claim 9, wherein the flange is disposed at an angle relative to the upper surface of the first riser bar; and wherein the angle is adapted to be complementary to a taper on a side wall of the manhole cover.
 11. The riser assembly as defined in claim 9, wherein the first riser bar further includes: a first end which extends between the interior and exterior surfaces and from the upper surface to the lower surface; a second end which extends between the interior and exterior surfaces and from the upper surface to the lower surface; and wherein the first riser bar is shaped so that the first end is opposed to the second end; and a first gap is defined between the first and second ends.
 12. The riser assembly as defined in claim 11, wherein the second riser frame comprises: a second annular riser bar having an upper surface, a lower surface, an interior surface, and an exterior surface; and wherein the upper surface of the second riser bar comprises the upper surface of the second riser frame, and the lower surface of the second riser bar comprises the lower surface of the second riser frame; a first end which extends between the interior and exterior surfaces of the second riser bar and from the upper surface to the lower surface thereof; a second end which extends between the interior and exterior surfaces of the second riser bar and from the upper surface to the lower surface thereof; and wherein the second riser bar is shaped so that the first end thereof is opposed to the second end thereof; and a second gap is defined between the first and second ends of the second riser bar and is generally vertically aligned with the first gap in the first riser bar; and wherein the second gap has a width.
 13. The riser assembly as defined in claim 12, wherein the expansion device extends between the first and second ends of the second riser bar, and is operable in a first direction to increase the width of the gap and thereby increase the size of a diameter of the second riser frame; and the expansion device is operable in a second direction to decrease the width of the gap and thereby decrease the diameter of the second riser frame.
 14. The riser assembly as defined in claim 11, wherein the expansion device is a turnbuckle assembly.
 15. The riser assembly as defined in claim 12, wherein the annular first riser bar is of a first diameter and the annular second riser bar is of a second diameter, and the first and second diameters are substantially the same when the expansion device is in a neutral position and is not activated to either expand or contract the second riser frame.
 16. The riser assembly as defined in claim 15, wherein the at least one spacer block is stationary relative to both of the first and second riser frames when the expansion device is activated to change the second diameter of the second riser frame.
 17. The riser assembly as defined claim 1, wherein the first riser frame is fixedly secured to the second riser frame via the at least one spacer block; and wherein the angle between the first and second riser frames is non-adjustable.
 18. A method of raising a manhole cover to the level of a top surface of an additional layer of paving material surrounding an existing manhole assembly; said method comprising the steps of: positioning an annular first riser bar above an annular second riser bar; inserting at least one spacer block between an upper surface of the second riser bar and a lower surface of the first riser bar to create an angle between an upper surface of the first riser bar and a lower surface of the second riser bar; vertically aligning the second riser bar, the first riser bar and the at least one spacer block with each other; securing the at least one spacer block to each of the first and second riser bars so that relative movement between them is substantially prevented; securing a flange to the first riser bar so that the flange extends upwardly and outwardly away from the upper surface of the first riser bar; resting the lower surface of the second riser bar against a horizontal support of the existing manhole assembly; and placing the manhole cover into a space bounded by the flange and the upper surface of the first riser bar; and resting a bottom perimeter of the manhole cover on the upper surface of the first riser bar.
 19. The method as defined in claim 18, further comprising the step of: activating an expansion device on the second riser bar; and changing the diameter of the second riser bar using the expansion device so that an exterior surface of the second riser bar engages an angled flange on the manhole frame.
 20. The method as defined in claim 19, further comprising the steps of: individually manufacturing a plurality of spacer blocks to have progressively different height dimensions and angled top and lower surfaces; inserting the individually manufactured spacer blocks at specific locations between the first and second riser bars that will result in the angle being created between the first and second riser bars; where the angle is complementary to the slope of the new layer of paving material.
 21. The method as defined in claim 20 further comprising the step of: welding a region of the lower surface of the first riser bar to an opposing region of the upper surface of the second riser bar. 